The potential functional significance of chromatin structural features associated with the (putative) control regions of three yeast genes, galactokinase, histone H2B and 35S rDNA will be evaluated, in order to determine whether there is a causative relationship between these structural features and the (unknown) features involved in transcriptional aspects of the control of gene expression in eukaryotic organisms. In parallel, work will be directed towards elucidating the physical forces involed in stabilizing anomalous control chromatin features and towards determining if there are any anomalous DNA conformational flexibility features associated with control sequence DNA. In vitro mutagenesis studies will be used to assess the dependence of control chromatin features and control sequence DNA conformational flexibility on DNA sequence. Various assays of gene expression level (viability, mRNA production, normal regulation) will be correlated with the physical data. A new technique for precise assessment of in nucleo DNA-protein interactions will be developed, to increase the sensitivity level for detecting anomalous chromatin structural features. A hybrid gene system will be used to try to develop a technique to obtain functional and structural data on one of the genes in a highly repeated gene set (35S rDNA). The goal of all these experiments is to gain some understanding of how eukaryotic cells control gene expression. An understanding of the bases for the control of gene expression is absolutely essential in understanding and solving a number of outstanding health problems, for example, cancer, aging and processes like abnormal development, which affect humans and other multicellular organisms. However, the latter systems are very complex. If one can gain an understanding of some of the bases for control of gene expression in a system like yeast, which has fewer complexities and is amenable to very favorable manipulations, this knowledge will be useful in helping to suggest approaches which can lead to understanding in the more complex systems.